Short wave tube



INVENTORS DIETRICH PRINZ ATTORNEY l llli s wxLHELM EBERHARD KUHLE j Ej)BY www W. E. KHLE ET AL SHQRT WAVE TUBE Filed Sept. 29, 1954 oct. 22,1935.

- Patented Oct. 22, 1935 UNITED STATES PATENT ori-"ICE,

SHORT WAVE TUBE wilhelm mmm xm ma 'Diemen Berlin,

Prinz aaaignora to Telefunken Ge:

Germany lellscliaft fr Drahtlose Telemphie m. b. H., Berlin, Germany, acorporation of Germany Application September 29, 1934, Serial No.746,215

In Germany October 7, 1933 4 Chlml. (Cl. Z50-27.5)

a closure and supporting means in the form of a' plate or disc andcorresponding to a press into l5 which several concentric metal tubesmay be hermetically sealed by annular seals very little if at all longerthan the thickness of the disc, and to unite the ceramic and the tubeenvelope with a vacuum-tight connection. In the fin- 20 ished structurerings of ceramic-insulating material are positioned between the metaltubes or leads and the overall length ofthe closure and supportingmember is a minimum.

The novel features which we believe to be g5 characteristic of ourinvention are set forth with particularlty in the appended claims, butthe invention itself will best be understood by reference to thefollowing description taken in connection with the accompanying drawingin which 30 Figure l is a longitudinal cross section of an electrondischarge made in accordance with our invention; Figure 2 is alongitudinal cross section of a modification of the electron dischargedevice shown in Figure 1 and embodying our invention; 35 and Figure 3shows a detail of construction.

. In Figure 1 the tubular metal anode envelope l has positioned withinit the grid-2, and the cathode 3. The electrodes 4, 5, and 8, in theform of concentric tubes, are supported in spaced rela- 40 tion byconcentric ceramic rings 1, i, and 9, which, with the ceramic plug l inthe base of the tubular conductor 6, form a flat or disc-like inset plugcorresponding to a press in a conventional tube. The leads are extendedperpendicu- 45 lar from the closure and supporting member into theenvelope, and form in the space outside the envelope a co-axial tubularsystem which is free from radio frequency radiations. The electrodes aresupported within the metal envelope solely 50 by the leads. By choosinga suitable length for the tube, conditions can be made so that a voltagenode will be set up at the closure member of insulating material,whereas a. voltage loop is formed at the lower end of the electrode sys-55 tem. An arrangement of this kind has the advantage that' only slightdielectric losses take place in the insulation material forming theclosure member. It will be seen that leads and l which support thecathode can be removed as a unit, in the event a replacement isnecessary, by 5 unscrewing lead 5, to which lead l is secured by memberl, from the tubular member il which is internally threaded to receivelead 5. An exhaust tube i2 is embedded preferably in the outer annularmember 1. It may be desirable in some cases to employ a cathode such asshown in Figure 2, comprising so-called twin or double prism lamentarycathodes i5 and i6 each consisting of three or more spaced parallelcurrent-carrying filaments connected together at their ends so that theylie in the edges of an imaginary prism. The filaments which denne a pairoi prisms are all interconnected at the' bottom as shown and supportedsolely bythe lead conductors. As a result, no central rod is requiredfor supporting the cathode, thereby eliminating the possibility of sucha rod forming an oscillatory system with the electron emitting lamentsof the cathode.

To make good seals between the ceramic insulating members and thetubular leads molybdenum tubes, which have proven especially suitable,are preferred. inasmuch as it is diillcult to make seamless molybdenumtubes, it is preferable to make them by riveting the edges of sheet Inolybdenum together, the riveting being done as best shown in Figure 3,only along the edges of the tube i1 not embedded in the ceramicinsulator.

A tube formed by riveting the edges of the molybdenum sheet together inthis way may then be smply fused to the ceramic insulator, provided themolybdenum tube has a suiliciently thin wall.

While we have indicated the preferred embodiments of our invention ofwhich we are now aware and have also indicated only one speciilcapplication for which our invention may be employed, it will be apparentthat our invention is by no means limited to the exact forms illustratedor the use indicated, but that many Variations may be made in theparticular structure used and the purpose for which it is employedwithout departing from the scope of our invention as set forth in theappended claims.

. What we claim as new isz- 1. An electron discharge tube for use athigh frequencies and comprising a tubular metal envelope open at oneend, member of ceramic material closing the open end of said envelope, aplurality of concentric tubular leads imbedded in said member, andelectrodes supported solely by said leads within said envelo 2. Anelectron discharge tube for use at high frequencies and comprising atubular metal envelope open at one end, a member o1' ceramic materialclosing the open end oi said envelope, a plurality oi concentric tubularlead conductors imbedded in said member and supported in spaced relationwith each other and with the envelope by said press. and electrodessupported on said lead conductors within the envelope.

3. An electron discharge tube for use at high frequencies and comprisinga'tubular metal envelope open at one end, an inset plug of ceramicmaterial closing the open end of said envelope, a plurality ofconcentric tubular lead conductors imbedded in said inset plug, andelectrodesincluding a cathode comprising a plurality o! parallel mamentsarranged to denne a pair of prisms supported by said lead conductorswithin the envelope.

4. Anl electron discharge tube for use at high frequencies/ andcomprising a tubular envelope open at onev end, a :dat inset plug o!ceramic materia] closing the open end of the envelope. a plurality ofconcentric tubular lead conductors imbedded in said inset plug andcomprising tubes made of thin molybdenum sheet extending pei-Vpendicularly from both sides of said inset plug with the edges or thetube riveted together only on the extended portions of the tube, andelectrodes supported on said lead conductors within said envelope.

WILHELM EBERHARD Kimm. DIETRICH PRINZ.

